Engine/Transmission (1998.5 - 2002) Low oil pressure

[azpete]

Was messing with the Smarty yesterday and checked the ECM codes. The normal ones where there but also low oil pressure and high oil pressure. Figured it was from my last oil change. Cleared the codes and checked again later. Only the low oil pressure code came back. The gauge reads a steady 40psi. Went for a drive, full throttle, idle or anywhere in between the needle never moves. Would this be a bad sender or maybe something more serious? The CEL has never came on.

 

[steved]

I would start by checking the actual oil pressure with a mechanical guage...



I would suspect a faulty sending unit... Cummins is your best bet to buy one... IIRC, $28.



steved

 

[Nate]

My truck has always had 60psi at idle and around 80 psi otherwise. Though that is reading the stock guage.

 

[rweis]

I think I remember there being a "dummy" value about 40 psi that can be displayed on the OEM gauge and you actually not have 40 psi. It should move with rpms to some extent. I put a mechanical gauge in and the OEM gauge does follow somewhat.



My mechanical gauge - early start cold engine runs 80 psi, 70 psi cruise (55 mph), 35 psi idle warmed up.



Bob Weis

 

[steved]

My mechanical gauge - early start cold engine runs 80 psi, 70 psi cruise (55 mph), 35 psi idle warmed up.



Bob Weis

Mine is up to 80PSI cold, 55-60psi cruise (any speed), and about 25-30psi idle (warm)... taken off a 1/4" feed line for a bypass filter about 12" from the pressure port... so my readings might be a touch low.



My guage is nowhere near what the mechanical guage reads... but as noted, the guage on the 03+ trucks is computer generated.



steved